Overwind stop for clock springs



May 24, 1960 FIG. 1.

H. S. ROGERSON OVERWIND STOP FOR CLOCK SPRINGS Filed March 9, 1959 FIG. 2.

INVENTOR HAROLD S- ROGERBON lTT RNEI United States Patent This invention relates to clock springs and the like and deals with a means for preventing overwinding of such springs.

Although the term clock spring will be used throughout the specification and claims, it is intended to cover all springs used for driving any device including clocks, watches, toys, mechanical tools and devices, scientific instruments, etc.

A common occurrence in winding springs of the character described is overwinding. This usually results in complete stoppage of the device driven by the spring,

I have observed by designing and testing that a hump in the outer run of the spring, if placed below the center of the spring, as determined by the anchor post and the winding post of the spring, will prevent overwinding under all conditions. The hump or distortion may be made in the spring itself or it may be incorporated in an auxiliary member that may be attached to the outer run of any spring. My invention contemplates both forms.

The means for the purpose described is simple, inexpensive, durable and eifective.

Other objects and advantages will become apparent as the description proceeds in conjunction with the drawing in which:

Fig. 1 is a side view of a conventionally wound spring showing how my invention may be incorporated in the spring itself;

Fig. 2 is a view similar to Fig. l where the overwind stop is made in an auxiliary member and attached to the spring;

Fig. 3 is a perspective view of an auxiliary member for the purpose described; and

Fig. 4 shows another form of an auxiliary member.

Referring to the drawing for a description of my invention, it will be seen that I have shown a conventional spring 11, wound on a post 12 and anchored to a post 13. In the outer run of the spring, and below the center of the spring with respect to the anchor post and the winding post, I incorporate a hump 14 in the spring, as shown in Fig. 1. I

In Fig. 3, I have shown an auxiliary member for attachment to any spring for the same purpose. This member is identified by numeral 15 and has on its upper end a pair of clamping fingers 16 adapted to span the width of a spring and hold the member 15 fixed in place. The member is formed with a hump 18 near its lower end similar to the hump 14 shown in Fig. 1. When in operative position, the fingers 16 engage opposite sides of a spring 17 and clamp the member 15 on the spring in position to bring the hump 18 below the center of the spring as shown by the winding post 12. This form of my invention is shown in Fig. 2, and is applicable to any existing device that is driven by a wound spring.

Instead of clamping the auxiliary member on the spring, I may anchor it on the anchor post 13, as shown in Fig. 4 and achieve the same results.

The heighth of the hump should be controlled'by the size of the spring, and in practice should be high enough to hold the outer run of the coil a sufiicient distance above the next inner coil to keep the two runs free and clear of each other for a distance of several degrees beyond the hump. The hump, being a distortion in the spring material itself, it will, under pressure brought about by the winding of the spring, display a certain amount of resiliency both vertically and horizontally thereby setting up new forces in a wound spring that tend to prevent overwinding of the spring.

The point of application of the hump may also vary. I have shown it as being applied slightly below the winding post 12, but it could be farther down and could even be below the post, the only requirement being that it hold the outer run of the coil away from the inner run a sufficient distance to provide the clearance space between the coils mentioned above.

I claim:

1. A clock spring having a hump in the outer coil thereof adapted to bear against the next inner coil and hold the said coils apart below the winding post of said spring, said hump being a transverse U-shaped bend in the springmaterial wherein said bend has a resiliency comparable to the said spring material to allow the bend to yield under pressure to generate a longitudinal force in said spring.

2. A clock spring having ahump in the outer coil thereof adapted to bear against the next inner coil and hold the said coils out of engagement for several degrees of circumference below the winding post of said spring, said hump being a transverse U-shaped bend in the spring material wherein said bend has a resiliency comparable to the said spring material to allow the bend to yield under pressure to generate a longitudinal force in said spring.

3. A clock spring having a hump in the outer coil thereof adapted to bear against the next inner coil below the winding post of said spring and hold the said coils apart for several degrees of circumference from said hump, said hump being a transverse U-shaped bend in the spring material wherein said bend has a resiliency comparable to the said spring material to allow the bend to yield under pressure to generate a longitudinal force in said spring.

4. For use with a clock spring, a member adapted to be attached to the outer coil of a spring, said member having a hump therein arranged to engage the next inner coil of said spring and hold the said inner coil and the said outer coil apart to a point several degrees of circumference below the winding post of said spring, said member being formed of spring material and the hump therein being a transverse U-shaped bendin said spring material wherein said bend has a resiliency comparable to the material of said member to allow the bend to yield under pressure. p

References Cited in the file of this patent UNITED STATES PATENTS 568,670 Erikson Sept. 29, 1896 1,458,333 Gill June 12, 1923 1,495,348 Odom May 27, 1924 2,937,866 Patented May 24, 1960 

